The invention concerns a geared motor, specifically a geared wiper motor for a vehicle, with an electric motor enclosed by a housing, with a gear located at the drive shaft of the electric motor enclosed by a gear housing, and with a brush mounting plate to hold brushes, where at least one ground brush connected to ground is present.
With geared motors of this type, the brushes are mounted on the brush mounting plate in such a way that the brushes ride on the outer edge of a current transformer in the electric motor. The ground brush is clinched with the grounded gear housing by means of a wire lead crimped into the gear housing. There can also be provision for clamping a plate connected to ground between the motor housing and the gear housing, where the ground brush is electrically connected with the ground plate.
A disadvantage of the present art is that crimping the wires in the gear housing or clamping the ground plate between the motor housing and the gear housing is not suited to mass production and results in an assembly that is not process-controlled.
The task on which the present invention is based is to develop a geared motor in which the connection between the ground brush and a grounded element is implemented with minimum manufacturing and assembly effort in a way that provides process control and functional reliability.
This task is solved in the case of a geared motor [of the type named at the beginning under the invention] by providing a connector element at the brush mounting plate, which has at least one brush locator to receive an electrical connection to the ground brush and at least one ground locator to receive an element connected to ground. The advantage of the invention is that crimping the wires in the gear housing connected to the ground brushes is dispensed with. In addition, a ground plate between the motor housing and the gear housing is not necessary. By using the connector element at the brush mounting plate, an achievement of the invention is that, firstly, an electrical connection with the ground brush can be implemented at the brush locator. Secondly, the ground locator is connected to a grounded element, thereby also connecting the ground brush to ground. In the assembly of a geared motor of this type, for example, the brush mounting plate is pre-assembled with the individual brushes and the connector element in pre-assembly. In a second assembly step, the brush mounting plate is installed into the geared motor, where only the ground locator of the connector element has to be attached or connected to a grounded element in order to ground the ground brush.
A particularly advantageous embodiment of the invention is characterized by the brush mounting plate having a connector opening and the connector extending partially through the connector opening, where the brush locator is positioned on the side of the brush mounting plate facing towards the brushes, and the ground locator is positioned on the side of the brush mounting plate facing away from the brushes. This has the advantage of achieving a spatial separation of the ground locator from the brushes through the brush mounting plate. This can prevent mutually induced malfunctions, of the brushes on the one hand and of the ground locator on the other, or of the grounded element which is retained by the ground locator.
An advantage is that provision can also be made to provide a direct, separable attachment of the ground locator to the grounded gear housing. The geared motor can then be removed without difficulty, particularly in the event of damage. In addition, this dispenses with a part to join the ground locator to the gear housing, which can save costs.
Provision can also be made for the ground locator to accommodate a plug connector which is injection-molded to the gear housing. By means of a positive molded connector of this type, a connection between the plug connector and the gear housing can be insured that is process-controlled and functionally reliable.
A further development of the invention provides for the ground locator to be jaw-shaped with two flexible tangs to hold the plug connector. A positive connection is achieved between the ground locator and the plug connector by using tangs of this type. Specifically, guide sections can be provided on the ground locator and/or the plug connector, which permit a better, specifically a detachable push-fit of the ground locator onto the plug connector. Volume production can be carried out with process control and functional reliability.
In one variation of the invention, provision is made for the connector element to be clamp-mounted to the brush mounting plate. A clamp mount has the advantage that bolts, rivets, adhesives and similar materials are not needed to attach the connector element to the brush mounting plate. Elaborate crimping tools for crimping the connector element to the brush mounting plate can be dispensed with.
Furthermore, there is an advantage when provision can be made for the connector element to have at least one protruding tab in the center area for the clamp retainer. The connector element can be clamped positively to the brush mounting plate by means of a tab of this type.
In another embodiment of the invention, the brush locator positions the contact of an additional component, specifically a thermoswitch element, which is electrically connected with the ground brush. The ground brush is therefore not grounded directly, but indirectly through the thermoswitch element.
Another embodiment of the invention provides for the brush locator to be welded or soldered to the electrical connection for the ground brush and/or to the contact for the additional component. By means of this type of welding or soldering, a permanent connection is made between the brush locator and the ground brush, or the additional component, respectively, in a simple and economical way.
In a preferred embodiment of the invention, the connector element is manufactured from sheet metal. Through appropriate handling and bending of the sheet metal, a connector element with the desired properties can be realized with a relatively low cost outlay.
In another further development of the invention, the brush mounting plate is retained by being clamped between the gear housing and the motor housing. The advantage is that no additional fasteners, such as rivets or bolts, for example, are required to attach the brush mounting plate. Clinching the brush mounting plate to the gear or motor housing can also be dispensed with. Specifically, in order to achieve a weight reduction in the gear housing, the gear and/or motor housings can be made from magnesium or aluminum. Clinching the brush mounting plates to housings of this type is, besides, not process-controlled. With a clamped mount of this type for the brush mounting plate, the brush mounting plate is installed between the gear housing and the motor housing during assembly. As part of the invention, provision can be made that with installation of this type, the ground locator of the connector element is guided into the connector molded onto the gear housing, for example. Assembly of this type is practicable with minimum assembly cost.
Further, it is advantageous to have a seal ring between the brush mounting plate and the motor housing, where the brush mounting plate is clamped between the seal ring and the gear housing or the motor housing. The installation of a seal ring of this kind has the advantage that firstly, the motor housing to gear housing interface is sealed against external environmental factors and secondly, that clamping forces affecting the brush mounting plate are evenly distributed.
In a further preferred embodiment of the invention, the brush holder plate is made of impregnated paper. Impregnated paper has proven to be particularly advantageous in practice for brush holder plates.